It is an unassuming, timeless marvel of mysterious origins and significant usefulness. It remains an artifact unto itself, providing illumination for those who need it in their lives, and moving on, ever ready to serve and light the darkness for the next master.
All spell casters gain their abilities through a form of demon possession. So in order to gain magical abilites, PCs must track down and trap demons. Of course there are some pretty powerful demons, if the demon is stronger than the PC, the PC could find themselves subjugated to the Demon's will.